Three-dimensional analysis of the tricuspid annular geometry in healthy subjects and in patients with different grades of functional tricuspid regurgitation.

Background: Accurate sizing of the tricuspid valve annulus is essential for determining the optimal timing of tricuspid valve (TV) intervention. Two-dimensional (2D) echocardiography has limitations for comprehensive TV analysis. Three-dimensional (3D) imaging of the valve provides a better understanding of its spatial anatomy and enables more accurate measurements of TV structures.

Objectives: The study aimed to analyze tricuspid annulus (TA) parameters in normal heart and in different grades of functional tricuspid regurgitation (TR); to compare TA measurements obtained by 2D and 3D echocardiography.

Methods: One hundred fifty-five patients (median age 65 years, 57% women) with normal TV and different functional TR grades underwent 2D and 3D transthoracic echocardiography. The severity of TR was estimated using multiparametric assessment according to the guidelines. Mid-systolic 3D TA parameters were calculated using TV dedicated software. The conventional 2D systolic TA measurements in a standard four-chamber view were performed.

Results: In mid-systole, the normal TA area was 9.2 ± 2.0 cm² for men and 7.4 ± 1.6 cm² for women. When indexed to body surface area (BSA), there were no significant differences in the 3D parameters between genders. The 2D TA diameters were smaller than those measured in 3D. The ROC curve analysis identified that all 3D TA parameters can accurately differentiate between different functional TR grades. Additionally, the optimal cut-off values were identified for each TA parameter.

Conclusions: Gender, body size, and age have an impact on the TA parameters in healthy subjects. 2D measurements are smaller than 3D parameters. The reference values for 3D metrics according to TR severity can help in identifying TA dilation and distinguishing between different functional TR grades.